Semiconductor Substrate with Receding Corners for Stress Relief
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Solution Overview
Problem
Existing semiconductor packages, such as Quad Flat Packs and grid array packages, face limitations in the number of external electrical connections due to their inherent structure, and are prone to stress and cracking at corner regions during assembly and testing, leading to defective packages.
Innovation Solution
A semiconductor device with a substantially rectangular substrate sheet featuring corner receding edges and apertures, where the encapsulating material covers both the die and the substrate sheet, including the corner regions to enhance adhesion and prevent cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a rectangular substrate sheet with sharp corners is used in grid array packages, then the package structure is simple and easy to manufacture, but stress concentrates at corner regions causing fractures and cracks during assembly and testing
Solution Approach 1:
The patent applies asymmetry by modifying the corner regions of the substrate sheet to have receding edges instead of sharp corners. This asymmetric modification redistributes stress away from the corner points, preventing stress concentration while maintaining the overall rectangular shape and manufacturing simplicity of the substrate.
Solution Approach 2:
The patent implements beforehand cushioning by providing an encapsulating material that covers the corner regions of the substrate sheet. This encapsulating material acts as a cushioning layer that absorbs and distributes stress before it can concentrate at the corners, preventing fractures and cracks during assembly and testing.
2Ease of manufacture
If the encapsulating material does not cover the corner regions of the substrate, then the manufacturing process is simpler, but the adhesion between mold compound and substrate is insufficient leading to corner detachment
Solution Approach 1:
The patent applies preliminary action by ensuring the encapsulating material is positioned to cover the corner regions of the substrate sheet before final curing or bonding occurs. This preliminary coverage ensures proper adhesion is established from the beginning, preventing corner detachment while maintaining a straightforward manufacturing process.
Data Source
AI summary
A semiconductor device is assembled from a rectangular substrate sheet. The substrate sheet has die mounting pads accessible from a first side and package mounting pads accessible from an opposite side. Corner regions of the substrate sheet have receding edges. A semiconductor die is attached to the substrate sheet such that electrodes or bonding pads of the die are mounted to respective die mounting pads of the substrate sheet. An encapsulating material covers the semiconductor die and the first side of the substrate sheet. Corner covering sections of the encapsulating material further cover the receding edges of the corner regions.